Mounting of fluidic temperature sensor in gas turbine engines

ABSTRACT

Fluidic oscillator positioned in the interior of a turbine nozzle vane used in a gas turbine engine. The inlet to the oscillator is connected to the leading edge of the vane and the outlet is connected to a throat portion in the nozzle so as to be at a lower pressure level. A closed tube extends from the oscillator to an exterior location where a transducer provides a signal output proportional to pressure oscillations in the sensor as a function of the gas temperature passing across the turbine nozzle.

United States Patent Inventor Jay I. Black Orange, Conn.

Appl. No. 880,528

Filed Nov. 28, 1969 Patented June 1, I971 Assignee Avco CorporationStrattord, Conn.

MOUNTING OF FLUIDIC TEMPERATURE SENSOR IN GAS TURBINE ENGINES 7 Claims,3 Drawing Figs.

U.S. Cl 73/346, 73/349, 4l5/l 15,4[6/96 Int. Cl. n G0lk 13/02, G0] k 11/26 Field of Search ..73/343, 339 A, 346, 349, 357;4l6/95,96;4l5/ll5;60/39.28

References Cited UNITED STATES PATENTS l/l953 Rainbow 3,348,414 10/1967Waters 73/343X 3,491,797 l/l970 Taplin 73/349X FOREIGN PATENTS l,5l2,8752/1968 France 73/339 Primary Examiner-Louis R. Prince AssistantExaminer--Denis F. Corr AttorneysCharles M. Hogan and Gary M. GronABSTRACT: Fluidic oscillator positioned in the interior of a turbinenozzle vane used in a gas turbine engine. The inlet totheoscillator isconnected to the leading edge of the vane and the outlet is connected toa throat portion in the nozzle so as to be at a lower pressure level. Aclosed tube extends from the oscillator to an exterior location where atransducer provides a signal output proportional to pressureoscillations in the sensor as a function of the gas temperature passingacross the turbine nozzle.

PATENTED JUN I |97| ENToR, JAY BLACK BY MM'W ATTORNEYS MOUNTING OFFLUIDIC TEMPERATURE SENSOR IN GAS TURBINE ENGINES The present inventionrelates to fluidic temperature sensors and more specifically to amounting for a sensor of this type in a gas turbine engine.

For a number of years the actual measurement of the turbine inlettemperature of a gas turbine engine has been a sought after objective.This is because the turbine inlet temperature must be held at a levelwhich is high enough to promote goodefficiency but to stay within thelimits of the material temperature capabilities.

Fluidic oscillations have been proposed for this purpose. Briefly, theycomprise a resonant chamber which has an inlet orifice connected to thegas, whose temperature is to be measured, and an outlet orificeconnected to a low pressure discharge. A splitter within the chamberpromotes an oscillation of the fluid in the chamber and this oscillationis directly proportional to the temperature of the gas passing throughthe oscillator.

One of the problems in using the fluidic oscillator for turbine inlettemperatures of over 2,000, common to high-performance gas turbineengines, is that the oscillator will quickly deteriorate throughprolonged exposure to the hot gas stream. Another problem is that theoscillator assembly tends to disturb the normal flow path through theengine and impair efficiency.

Accordingly, it is an object of the present invention to provide amounting arrangement for a fluidic oscillator and a gas turbine enginewhich will enable prolonged use of the oscillator to measure elevatedgas temperatures and will have a minimum effect on the efficiencies ofthe engine.

In one aspect of the invention these ends are achieved by providing afluidic oscillator of the above general type in a cooling passage of aturbine inlet nozzle vane. The inlet of the oscillator is connected toan upstream portion of the vane and the outlet to a lower pressuredischarge. Thus, the turbine inlet temperature is measured while thebody of the fluidic oscillator iskept at a temperature which permitsprolonged operation.

The above and other related objects and features of the presentinvention will be apparent from a reading of the description of thedisclosure found in the accompanying drawing and the novelty thereofpointed out in the appended claims.

In the drawing:

FIG. I is a longitudinal section view of a mounting for a fluidictemperature sensor embodying the present invention along with thecooperating portions of a gas turbine engine.

FIG. 2 is a greatly enlarged view of the fluidic oscillator shown inFIG. 1 and taken on lines 2-2 of FIG. 1.

FIG. 3 is an alternate mounting for a fluidic temperature sensorembodying the present invention.

Referring to FIG. 1 there are shown those portions of a gas turbineengine with which the present invention is concerned. For completedetails of a type of engine with which the present invention may beemployed, see US. Pat. No. 3,088,278 in the name of Anselm Franz, issuedMay 7, l963, entitled Gas Turbine Engine and of common assignment withthe present invention. However, for purposes of explaining the presentinvention, the engine components shown in FIG. 1 are sufficient.

In FIG. 1 a compressor, including a last-stage centrifugal impeller 10,discharges air to a diffuser assembly 12 which discharges the air into acombustor assembly 14, only the aft end of which is shown. A suitablefuel nozzle injects fuel into the combustor and the mixture is ignitedby suitable means well known in the art to provide a propulsivehot gasstream. The hot gas stream is discharged from the combustor 14 to aturning duct assembly comprising inner and outer annular members 16 and18.

The downstream end of the turning duct assembly discharges across aturbine nozzle assembly 20. The turbine nozzle assembly comprises aseries of radial vanes 22 secured to inner and outer annular supportmembers 24 and 26 and shaped to form converging, diverging flow paths.For normal operation of the engine the minimum flow area section, orthroat T, of the turbine nozzle assembly is choked.

From the turbine nozzle assembly 20 the hot gas stream expands across afirst stage 28 of a turbine assembly, an interstage vane assembly and asecond stage of the turbine assembly. From there the hot gas streampasses to a power turbine for providing a rotatable output or through ajet nozzle to provide a reaction propulsion thrust.

A path for cooling air through vanes 22 is provided by passageways 36 inthe vanes. These passageways are supplied with cooling air through a gap62 at the periphery of the compressor impeller 10 which permits ametered flow of pressurized air to pass through ports 54 and 62 in anengine frame assembly 50 and into the radially inward end of vane 22.From there the air flows longitudinally through the passageways 36 invanes 22 and may be, in part, discharged through various openings in thevanes to cool the outer surface thereof. At the radially outward end ofthe vanes 22 the air is discharged through perforations 66 in the ductassembly I6 to the gas stream entering the turbine nozzle assembly tocool leading edges of the vanes 22.

A fluidic oscillator, generally indicated by reference character 35,comprising a resonant chamber 34 is positioned in the cooling passageway36 for one of the vanes 22. The oscillator has an inlet tube 38,including an orifice, extending to an upstream portion 40 of the turbinenozzle vane. As shown herein, the tube 38 extends to the leading edge ofvane 22. However, for other applications the end of tube 38 may beplaced in the upstream convex side of vane 22 to minimize contaminationof the oscillator 35 by foreign objects. An outlet tube 42, including asecond orifice, extends to the convex side of the vane 22 and, as hereinshown, discharges at the throat T of the turbine nozzle assembly. Asplitter element 44 is positioned in the chamber 34 to produceacoustical pressure waves whose frequency of oscillation is dependentsubstantially on the temperature of the gas entering the chamber 34 fromthe inlet tube 38, as is well known in the art.

A tube 46 extends from the chamber 34 out of the vane 22 to a connectorassembly 48 positioned in the frame assembly 50 of the engine. Aseries-connected tube 52 extends from the connector assembly 48 throughthe opening 54 and through a hollow strut 56 in the compressor diffuserto a closed end signal-attenuating coil assembly 53. A pressuretransducer 60 is connected to the line 52. The transducer 60 is adaptedto provide an electrical signal output in response to the pressureoscillations in tube 52. The transducer may be one of a number oftransducers well known in the art that may be employed for this purpose.The transducer 60 is calibrated so that its output is directlyproportional to the temperature of the gas entering the inlet tube 38 ofthe fluidic oscillator.

During operation of the engine, a pressure differential exists acrossthe inlet and outlet ports of the fluidic oscillator. This causes a flowthrough the resonant oscillator chamber 34 and the splitter 44 causespressure oscillations which are proportional to the temperature of thegas flowing through the oscillator 35. The temperatures that theoscillator senses are extremely high and prolong exposure of the chamber34 and inlet and outlet tubes 38 and 42 would cause them to deteriorate.However, the cooling air which passes over the fluidic oscillatormaintains its temperature at a level which enables prolonged operationin sensing the hot gas temperatures at the inlet of the turbine nozzlewithout significant deterioration. In addition, the placement of thesensor inside a turbine nozzle vane minimizes the effect of the sensoron the performance of the engine.

As illustrated in FIGS. 1 and 2, the sensor inlet and outlet arepositioned entirely within the vanes. The inlet 38 is exposed to thetotal pressure of the gas stream entering the turbine nozzle and theoutlet port is exposed to the pressure at the throat in the nozzleassembly which is the lowest pressure existing in the turbine nozzleassembly. This pressure ratio is generally sufficient to provideacceptable results in the measurement of temperature by the oscillator.

The arrangement of FIG. 3, however, may be employed to produce even moreaccurate results. In this figure a modified fluidic oscillator 35 ispositioned in a vane 22. The inlet 38 extends to the leading edge of thevane 22 but an outlet port 68 extends longitudinally through the vane 22and discharges downstream of the turbine assembly. This downstreampressure is substantially lower than the pressure at the throat T in theturbine nozzle and it insures that the fluidic oscillator is chokedthroughout the normal operating ranges of the engine, thereby making theoscillator more accurate at lower engine operating speeds.

The oscillator described above is a highly compact and reliable assemblythat may be employed with particular advantage in gas turbine engines.However, it may be employed to measure other hot gas streams with equaladvantage. Accordingly, the scope of the invention should be determinedsolely by the appended claims.

Having thus described the invention, what I claim as novel and desire tobe secured by Letters Patent of the United States l. A fluidictemperature sensor assembly for a gas turbine engine, said assemblycomprising:

an aerodynamic vane extending across a hot fluid stream in said gasturbine;

means for providing a cooling-air passageway through said vane;

a fluidic oscillator having an oscillating chamber positioned in saidcooling passageway means and having an inlet extending to an upstreamportion of said vane and an outlet extending to a discharge point at apressure lower than the pressure at said inlet; and

means for sensing the pressure oscillations in said fluidic oscillatoras a function of the temperature of said fluid stream.

2. A fluidic temperature sensor as in claim 1 wherein said aerodynamicvane comprises a vane of a plurality of vanes comprising an inlet nozzlefor a turbine assembly, whereby said fluidic temperature sensor sensesturbine inlet temperature.

3. A fluidic temperature sensor as in claim 2 wherein said turbinenozzle vanes are shaped to provide converging, diverging passagewaysthrough said turbine nozzle to provide a choked condition at a throatportion and wherein said inlet extends to the leading edge of said vaneand said outlet extends to the throat portion of said turbine nozzle,thereby providing said low-pressure discharge.

4. A fluidic temperature sensor as in claim 2 wherein said outletextends to'a point downstream of said turbine assembly.

5. A fluidic temperature sensor as in claim 2 wherein the means forsensing the pressure oscillations in said chamber comprises:

an elongated closed tube connected to said chamber and extending awayfrom said turbine nozzle vanes;

a transducer exposed to pressure oscillations in said tube for providinga signal output as a function of the pressure oscillations in saidchamber.

6. A gas turbine engine comprising:

a compressor for pressurizing a source of air;

a combustor for receiving pressurized air from said compressor and forgenerating a hot gas stream;

a turbine assembly downstream of said combustor and having a turbineinlet nozzle through which said hot gas stream passes, said turbinenozzle comprising a plurality of radially extending hollow vanes;

means for providing a flow path for pressurized cooling air from saidcompressor through the interior of said vanes;

a fluidic oscillator connected to the hot gas stream passing throughsaid turbine nozzle and being positioned in the interior of said vanes,whereby the exterior of said fluidic oscillator is maintained at thetemperature of said cooling air; and

means exterior of said turbine nozzle assembly for providing a signaloutput proportional to the pressure oscillations in said fluidicoscillator.

7. A gas turbine engine as in claim 6 wherein said fluidic oscillatorcomprises:

a chamber positioned in the interior of one of said turbine nozzle vanesand having an inlet extending to the leading edge thereof and an outletextending to a throat portion in said turbine nozzle assembly;

said means for providing a signal output comprises a closed tubeconnected to said oscillating chamber and extending away from saidturbine noule assembly and a transducer connected to said tube forproviding a signal output proportional to the oscillations in said tube.

1. A fluidic temperature sensor assembly for a gas turbine engine, saidassembly comprising: an aerodynamic vane extending across a hot fluidstream in said gas turbine; means for providing a cooling-air passagewaythrough said vane; a fluidic oscillator having an oscillating chamberpositioned in said cooling passageway means and having an inletextending to an upstream portion of said vane and an outlet extending toa discharge point at a pressure lower than the pressure at said inlet;and means for sensing the pressure oscillations in said fluidicoscillator as a function of the temperature of said fluid stream.
 2. Afluidic temperature sensor as in claim 1 wherein said aerodynamic vanecomprises a vane of a plurality of vanes comprising an inlet nozzle fora turbine assembly, whereby said fluidic temperature sensor sensesturbine inlet temperature.
 3. A fluidic temperature sensor as in claim 2wherein said turbine nozzle vanes are shaped to provide converging,diverging passageways through said turbine nozzle to provide a chokedcondition at a throat portion and wherein said inlet extends to theleading edge of said vane and said outlet extends to the throat portionof said turbine nozzle, thereby providing said low-pressure discharge.4. A fluidic temperature sensor as in claim 2 wherein said outletextends to a point downstream of said turbine assembly.
 5. A fluidictemperature sensor as in claim 2 wherein the means for sensing thepressure oscillations in said chamber comprises: an elongated closedtube connected to said chamber and extending away from said turbinenozzle vanes; a transducer exposed to pressure oscillations in said tubefor providing a signal output as a function of the pressure oscillationsin said chamber.
 6. A gas turbine engine comprising: a compressor forpressurizing a source of air; a combustor for receiving pressurized airfrom said compressor and for generating a hot gas stream; a turbineassembly downstream of said combustor and having a turbine inlet nozzlethrough which said hot gas stream passes, said turbine nozzle comprisinga plurality of radially extending hollow vanes; means for providing aflow path for pressurized cooling air from said compressor through theinterior of said vanes; a fluidic oscillator connected to the hot gasstream passing through said turbine nozzle and being positioned in theinterior of said vanes, whereby the exterior of said fluidic oscillatoris maintained at the temperature of said cooling air; and means exteriorof said turbine nozzle assembly for providing a signal outputproportional to the pressure oscillations in said fluidic oscillator. 7.A gas turbine engine as in claim 6 wherein said fluidic oscillatorcomprises: a chamber positioned in the interior of one of said turbinenozzle vanes and having an inlet extending to the leading edge thereofand an outlet extending to a throat portion in said turbine nozzleassembly; said means for providing a signal output comprises a closedtube connected to said oscillating chamber and extending away from saidturbine nozzle assembly and a transducer connected to said tube forproviding a signal output proportional to the oscillations in said tube.